Means for securing printing plates to their cylinders under tension



Feb. 2, 1954 T, R ZIEBELL 2,667,833

MEANS FOR SECURING PRINTING PLATES To THEIR CYLINDERS UNDER TENSION Filed NOV. 2, 1951 Patented Feb. 2, 1954 UNITED S'if fearaur l.ori-ice MEANS EUR SECURING PRINTING PLATES T@ 'ECHEKR 'JYLINDERSUNDER' TENSIONv Theodore R. Ziebell, Milwaukee, 'Wis., .assignor to C. B. Cottrell` it Sons Company,v W'esterly,.R.I., a corporation of`Delaware Application November 2, 1951, Serial No.'25.4,564

(Cl. Mil-'378) pelled along the cylinder grooves to and from their plate engaging positions by worm gears carried by the hooks and engaging the cylinder racks, the cylinder racks frequently become Worn and broken because of the necessarily limited engagement of only one or two of the teeth oi the `worm gears with the teeth of the cylinder racks.

This invention is directed to plate tensioning means for overcoming these rack failures-by providing a plate tension hook comprising coacting stationary and movable members; the stationary member having a row or teeth for extended, en-

gagement with the teeth oi a cylinder rack '-to prevent endwise movement of the stationary member; the movable member, which carries the printing plate engaging jaw, being slidable along vthe stationary member to exert tension on-the 'printing plate for securing it to its cylinder.

This invention is also directed to a plate ten- 'sion hook having novel features of construction whereby the manually operated adjusting screw, which connects the stationary and movable members of the 'plate tension hook, is rotatably mounted against endwise movement in the movable member and has a screw threaded engagement with the stationary member.

This invention is also directed to a plate tension hook in. which gearing is provided for operatively connecting the adjusting screw with a removable key or other suitable instrument.

A practical embodiment of my invention is represented in the accompanying drawings, in which Fig. 1 represents a detail plan viewshowing a portion of' a printing plate secured to its cylinder.

Fig. 2 represents a similar view on a much larger scale.

Fig. 3 represents a detail longitudinal section 'taken in the plane of the line 3 3 of Fig. 2;

Fig-ll represents a detail cross section taken in the plane of the line fil-t of Fig. 2;

Fig. 5 represents a detail cross section taken in the plane of the line 5 5 of Fig. 2;

Fig. 6 represents a side view of a key suitable for use in operating the movable hook member and for turning one lof the locks which slidably hold the movable member in its cylinder.

Fig. 7 represents an edge View of the said key. The grooved'baseon which the printing plates are to be secured under tension is shown `as a `plate cylinder II having spaced undercut spiral grooves E2 provided `.aflongtheir bottoms with toothed racks I3.

The marginal edge of the printing plate Ill is shown as having a reverse bevel formed by inclining-the top surface-of the edge inwardly and downwardly, as shown at i5, to be engaged by the plate tensioning 4jaw of `the yplate tension hook to be immediately described.

The. plate-tension hookior securingthe printing plate IA on the cylinder l byV tension is shown as comprising-astationary member I6 and a movable .member Il Yin'fwhich the stationary member is housed.

The-stationary member `IIi is shown as provided -withfa` row of teeth; t8 along itsv bottom for extended engagement with'the teeth of the cyl- .inder groove rack I3' to lock the stationary mem- .ber against endwise movement along the cylin- .der `groove I2 when the plate tension hook has been inserted intothe said groove at the ldesired point. along the sameadjacent the marginal edge of the` printing plate I4.

Theplate tensioning, jaw I9 is turnably mou-nted on a clamp. screw.20 which has a threaded engagement vwith the movable member II of the plate tension hookabout midway its ends. This jaw l@ yhas a reversebevel formedfby inclining the end surface of the jaw inwardly and upwardly as shown at'2l for frictional engagement withthe inclined top surface I5 ,of the marginal edge of the printing plate to exert tension thereon.

The movable hook member il' of the plate tension hook isprovided with two manually turnable 'double winged locks 22, 23 mounted in the movable member near its ends upon opposite sides of the plate tensioning jaw Iii, in position to be turned into theismall` grooves 2t extending along the opposite side walls of the cylinderv groove I2. "This movable hook member Il has a Vlongitudinal bottom groove Il* which houses thestationary member I6; the side walls .of said `groove slidably engagingV the side Walls of the Stationary member.

The manually turnable double winged lock 22 is shown as having an angular axial bore 25 for receiving the angular shank 26 of a suitable key 2'? for turning the said lock 22 into and out of sliding engagement with the side grooves 24.

The manually turnable double winged lock 23 is shown as having an angular axial bore 28 for receiving the said angular shank 26 of the key 2'I.

The usual spring pressed balls 29, 30 may be employed to frictionally engage the double winged locks 22, 23 to yieldingly hold them in their withdrawn and extended positions. that the plate tensioning jaw I9 is located between the two double-winged locks 22, 23.

The manually operated means for sliding the movable hook member along the stationary hook member, which is housed therein, is constructed, arranged and operated as follows: f

An adjusting screw 3l which is located in the bottom groove Il* of the movable memberv It will be notedV -connecting the two members and a manually op- Y erated gearing for rotating the screw to slide the movable member along the housed stationary member for securing the plate on the cylinder under tension.

2. A cylinder having spaced grooves, a printingY plate and a plate tension hook comprising a operatively connects the two hook members I6,-

I'I, the head of the said screw being rotatably mounted against endwise movement in the movable member I7 and the threaded shank of the said screw being passed through and having a screw threaded engagement with the stationary member IE of the said hook within said bottom Y The adjusting screw 3| has integral therewith a bevel gear 32 which meshes with a bevel gear 33 whose shank is rotatably mounted in the enlarged portion of the axial bore 28 of the turnable lock 23. This bevel gear 33 is provided with a smaller axial bore 34 for receiving the smaller shank 35 of the key 21 which may be inserted through the angular bore 28 of the gear 33.

In operation, the plate tension hooks are inserted into the cylinder grooves I 2 in proper positions to cause the rofws of teeth I8 of the stationary hook member I6 to bring the plate tensioning jaws I9 into position to receive the marginal edges of the plate I4 between the inclined Y end surfaces 2| of the jaws and the peripheral surface of the cylinder II, the double winged locks 22 and 23, which are located upon opposite sides of the tensioning jaw I9, being first turned into their side grooves 24 to slidably hold the plate tensioning hook within the groove. The clamp screw 20 may then be turned to frictionally engage the marginal edges of the plate I4. The shank 35 of the key 21 may thenbe inserted into the angular bore 34 of the gear 33 to turn it and itsmeshing gear 32 of the screw. 3I to cause the screw, because of its threaded engagement with the stationary hook member I6, to slide the movable hook member I'I along the stationary ,hook member I 3 to cause the jaw I9 to exert ten- Vsion upon the printing plate I4 to secure it firmly on the cylinder I. Y Y l It will be understood that while the plate hold- Ving means is herein shown and described in connection with a curved printing plate and a spirstationary member having means for locking it in a cylinder groove against endwise movement, a movable member having a longitudinal bottom groove housing the stationary member, means for slidably holding the movable member in its cylinder groove, a plate tension jaw carried by said movable member independently oi said movable member holding means, a screw located in said bottom groove and rotatably mounted against endwise movement in the movable member and threaded into the stationary member, a gear on said screw, and a manually operated meshing gear carried by the first named means for rotating the screw to slide the movable member along the housed stationary member for securing the plate on the cylinder under tension.

3. A cylinder having spaced grooves provided with toothed racks, a printing plate and a plate tension hook, said plate tension hook comprising a stationary member having a row of teeth for extended engagement with one of said racks to lock the stationary member against endwise movement, a movable member having a longitudinal bottom groove housing the stationary member,` two spaced manually turnable locks for slidably holding the movable member in its groove, a plate tension jaw carried by said movable member between said locks, and a manually operated means for sliding the movable mem-V ber along the housed stationary member to secure the plate on the cylinder under tension.

4. A cylinder having spaced spiral grooves provided with racks, a printing plate and a plate tension hook comprising a movable member having a longitudinal bottom groove, two manually operated locks for slidably holding the movable member in its cylinder groove, a stationary member housed in said bottom groove of the movable member and provided with a row of teeth for extended engagement with a cylinder groove rack to lock the stationary member against endwise movement, a plate tension jaw mounted on said movable member between said locks and having a reverse bevel engagement with a marginal edge of said plate, and manually operated means for sliding the movable member along the stationary member to securegthe plate on the cylinder under tension.

5. A printing plate tension hook comprising aV the cylinder groove, and means for sliding the' movable member along the housed stationary member.

6. A printing plate tension hook comprising a stationary member provided with a row of teeth for extended engagement with a plate cylinder groove rack for locking the stationary member against endwise movement along the cylinder groove, a movable member having a longitudinal bottom groove housing the stationary member, -a plate tensioning jaw carried by the movable member, means on both sides of the said jaw for slidably holding the movable member in its cylinder groove, and means for sliding the movable member along the housed stationary member' THEODORE R. ZIEBELL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 809,229 Storm Jan. 2, 1906 838,039 Mehle Dec. 11, 1906 998,447 Andrews July 18, 1911 1,619,650 Brugmann Mar. l, 1927 2,224,555 Sweet Dec, 10, 1940 2,465,252 Meyer Mar. 22, 1949 2,582,960 Burgess Jan. 22, 1952 

